Scientists Hack Plants With Nanotubes to Supercharge Photosynthesis

Carbon nanotubes in this leaf's chloroplasts glow orange in the near infrared. (Juan Pablo Giraldo and Nicole M. Iverson)

By incorporating nanomaterials into the energy-producing structures inside plants, scientists have managed to turn an ordinary plant into a super plant (no phone booth required). The team used carbon nanotubes to enhance the photosynthetic ability of chloroplasts and triple a plant’s energy-producing potential.

The carbon nanotubes expand the range of light wavelengths that activate a plant’s photosynthetic systems. Even at their most productive, plants can normally only absorb about 10 percent of full sunlight. So, science to the rescue.

Scientists first wanted to see how easily they could slip nanotubes into chloroplasts, the cellular factories that turn sunlight and carbon dioxide into energy and sugars. Turns out, it wasn’t difficult at all, they report March 16 in Nature Materials. Nanotubes coated in single-stranded DNA slipped right through the chloroplast membranes of Arabidopsis thaliana, a type of cress that’s often used in plant research.

Next, the team wanted to see how the nanotubes affect photosynthesis. To do this, they used a dye that changes color when it absorbs electrons. These charged particles are produced during photosynthesis, so the more photosynthesis that’s going on, the more dramatic the change in the color of the dye. This is what the scientists saw when they looked at plants that had been transformed with carbon nanotubes.

Then, the team wanted to see if a different type of nanoparticle could help the cells clear compounds known as free radicals. These compounds damage DNA and attack pigments, photosynthetic reaction centers, and proteins. Nanoparticles of metallic cerium, called nanoceria, have a lattice-like structure that can trap radicals; the team found 27 percent fewer radicals in the chloroplasts containing nanoceria, compared to those that were untreated.

Lastly, the team showed that carbon nanotubes are capable of detecting nitric oxide in the environment, expanding the range of sensory capabilities in the plants.